The idea of 'fitness landscapes' is central to this paper and requires development. Kauffman has remarked :

Biologists have long harbored images of fitness landscapes, where the peaks represent high fitness, and populations wander under the drives of mutation, selection and random drift across the landscape seeking peaks, but perhaps never achieving them. The idea of fitness peaks applies at many levels. (1995: p. 27)

The idea of fitness landscape is an image of the contemporary state of a co-evolutionary system. The system is co-evolutionary because any change in any element in it affects all the other elements and can result in a transformation of the whole structure of the landscape itself. In the account given here an analogy is drawn between biological species and school types. There are two clear fitness peaks - note that fitness is not being equate with achievement. Rather it is a matter of the stability of the form. One is high success and the other is minimal success. The relationship of schools with the socio-spatial landscape means that there is no direct route between these two positions. The middle situation represents a kind of broad plateau which is connected to the two peaks, but in a way which is complicated by the determinant (note complexity doesn't abandon determinism - this is not postmodernism! Complexity just sees determination as complex and contingent, not as absent) effects of the related socio-spatial fitness landscape describing the form of residential patterns. Schools can move from low attainment to moderate and from moderate to high, although in order to reach the peaks of attainment there must be the adaptive acquisition of the characteristic of selection of pupils by ability. A school could suffer catastrophic decline. I am aware of instances of such dramatic change in primary schools, but not so far in secondary where the scale means that small changes in pupil characteristics or staff capacities don't produce massive changes. The sheer size of these institutions imposes a kind of damping effect.

The idea of landscape is not a metaphor. It is an analogy describing any complex co-evolutionary system in the domain between simple linear order and chaos. The situation being described in this paper involves the laying of one fitness landscape, that of the school system, on top of another, that of residential space.